The overall objective of the proposed investigation is to resolve problems associated with the captive breeding of the nine-banded armadillo (Dasypus novemcinctus). This species offers an array of unique traits which are of great potential utility in studies of both physiology and pathology. Previous attempts at captive breeding have been unsuccessful thus inbred strains for laboratory studies are lacking. Preliminary studies in this laboratory directed toward the delineation of an annual reproductive cycle in captive armadillos indicate that the female, but not the male, is infertile. In association with anovulation, but not necessarily causitive to it, is an observed adrenal component of circulating progesterone. Whether or not this adrenal activity is a causitive factor precipitated by captivity is currently under investigation. Proposed studies include correlations of circulating steroid levels and histology between captive and free ranging animals. Ovarian responsiveness to exogenous gonadotropins will also be correlated to adrenal activity and the role of ovarian and adrenal steroids in the delay of implantation will be delineated.